Moving stairway protective device



Oct. 19, 1937. A. E. HANDY 2,096,583

MOVING STAIRWAY PROTECTIVE DEVICE Filed Feb. 20, 1937 2 Sheets-Sheet lmwkm mvemon WW ATTORNEY Oct. 19, 1937. A. E. HANDY 2,096,583

MOVING STAIRWAY PROTECTIVE DEVICE Filed Feb. 20, 1937 2 Sheets- Sheet 2v v j 'r j ICl D- Q... L To n L 2 5 ulnuL1- u [L 55 [5,50 &1 54/ I3flAILAZM H'WINVENTOR m ATTORNEY Patented Oct. 19, 1937 UNITED STATESPATENT OFFIQE MOVING STAIRWAY PROTECTIVE DEVICE Application February 20,1937, Serial No. 126,784

6 Claims.

The invention relates to protective devices for moving stairways.

Moving stairways are provided with moving handrails for the convenienceof persons using the Stairways. These handrails are arranged one on eachside of the stairs, and are driven in synchronism with the steps. It hasbeen found desirable to provide a traction drive for the handrails andsuch drives have been the practice for a considerable number of years.With such a drive it is possible for the handrails to slip with respectto their driving sheaves. It sometimes happens that a handrail does slipdue to a force being exerted on the handrail opposite to that exerted todrive it. This force may be an accidental one or one due to thedeliberate acts of individuals such as where the handrails are ridden orwhere one or more persons on the floor adjacent the stairway take holdof the handrail and pull or push back on it. The force exerted may besuificient to stop the handrail or it may only slow it up. In eithercase, there is relative motion between the steps and the handrail,resulting in a feeling of insecurity on the part of passengers holdingthe handrail which may cause them to fall. It is desirable, therefore,that the stairway be brought to a stop when such conditions arise. Thisminimizes the possibility of accidents due to such conditions.

It is the object of the invention to stop the driving of a movingstairway whenever the slow.- ing down or stopping of a handrail occurs.7

The invention involves the provision of a protective device responsiveto the speed of a. handrail for controlling the operation of the drivingmechanism for the steps and the handrails to cause the stopping of thismechanism in the event that the speed of the handrail falls below apredetermined value. In carrying out the invention as applied toelectric driving mechanism, a speed responsive governor may be providedfor each handrail to be driven thereby and arranged with contacts forcontrolling the supply of electric power to the driving mechanism. Eachgovernor is set to operate its contacts at a handrail speed such thatoperation of the driving mechanism to drive the steps and the handrailsis discontinued when the speed of movement of either handrail falls acertain amount below the speed of step movement.

Features and advantages ofthe invention will become apparent from thefollowing description and appended claims.

In the drawings:-

Figure 1 is a diagrammatic representation in side elevation of a movingstairway embodying the invention; and

Figure 2 is a simplified wiring diagram of circuits for controlling amoving stairway in accordance with the invention.

Referring to Figure 1, the moving stairway ex tends between a lowerlanding I9 and an upper landing II. It comprises an endless series ofsteps l2 driven at the upper end of the stairway by means of sprocketwheels through running gear chains, a sprocket wheel and chain beingarranged on each side of the stairway. A sprocket wheel and running gearchain are illustrated diagrammatically for one side of the stairway, thesprocket Wheel being designated 13 and the chain I4. The sprocket wheelsare mounted on and driven by the main drive shaft l5 of the stairway.This drive shaft, in turn, is driven by an electric motor l6, throughreduction gearing l'l, sprocket wheel l3, driving chain 19 and sprocketwheel 20 secured to shaft l5, chain l9 and wheels I8 and 20 also beingdiagrammatically illustrated.

A machine or stairway'brake is provided for the main drive shaft. A formof brake has been schematically illustrated which acts to stop adescending stairway and to prevent downward movement of an ascendingstairway after the supply of power to the driving motor has beendiscontinued. The brake comprises a disc 2i driven: by the main shaftthrough spring pressed brake shoes 22 acting as a clutch. Although brakeshoes are illustrated cooperating directly with the main shaft, suchillustration is for convenience, it being understood that the brake mayact directly on driven sprocket 2|]. Associated with the disc is. aringmember 23 having a plurality of internal pawl teeth 24 for receivingpawl 25. This pawl is biased about a fixed pivot for cooperating withthe teeth and is controlled by an electromagnet 21 through link 28 andlever 30. The electromagnet is controlled so as to be energized anddeenergized simultaneously with the driving motor. When theelectromagnet is energized, the pawl is pulled into position where it isclear of the pawl teeth. This releases the brake, permitting the disc 2|to be freely driven by shaft l5. Upon deenergization of theelectromagnet when the stairway is descending, the pawl swings intoposition to engage the next tooth on ring member 23, bringing the discto an immediate stop. Thereupon the brake shoes 22 act to exert abraking force on the main shaft to bring the stairway to a stop. Upondeenergization of the electromagnet when the stairway is ascending, thesupply of power to the motor being discontinued, the stairway is broughtto a stop by forces due to friction, and the brake acts to preventreversal of the stairway should the load thereon tend to effect suchreversal.

The stairway has two endless moving handrails, one at each side thereof,operating at substantially the same speed as the steps. The handrail 3|for one side of the stairway is shown and is diagrammaticallyillustrated as driven from main drive shaft l5. This is effected bymeans of a sprocket wheel 32 on the main drive shaft driving sprocketwheels 33 and 34 secured respectively to handrail newel wheel 35and-handrail return wheel 36 of the tightening mechanism designatedgenerally as 31. There is also pro-' vided a newel wheel 38 forthehandrail at the lower end of the stairway around which the handrailpasses. the other side of the stairway is the same. Each of the newelwheels 38 at the lower end of the stairway is arranged to operate aspeed responsive device. The speed responsive device for the lower newelwheel shown is illustrated as a gov-' ernor operated switch 40 drivenfrom the newel wheel by means of sprocket wheels 4| and 42 and chain 43.This switch is set so as to close just as the handrail comes up tosubstantially full running speed and to open again when the handrailfalls below this speed. These speed responsive switches are arranged tocontrol the driving motor l6 for the stairwayand the releaseelectromagnet 21 for the stairway brake.

A wiring diagram embodying this control .is shown in Figure 2. It is tobe understood that the control may be embodied in any moving stairwaycontrol system, a simplified system for a direct current driving motorbeing illustrated for convenience. No safety devices are included in thewiring diagram. other than the devices responsive to the speed of thehandrails. An up starting button, a down starting button and a stopbutton are provided at each end'of the stairway, preferably located onthe face 'of the balustrade as indicated at 44 for the upper end of thestairway and at 45 for the lower end of the stairway. In the wiringdiagram the up starting buttons are designated 46 and 41, the downstarting buttons 48 and 50 and the stop buttons 5! and 52. r i

Upon the pressing of either up starting button, coil 53 of the updirection switch U is energized. This switch operates to engage contacts54 .to energize the release electromagnet 21 of the stairway brake,moving the pawl into position to clear the pawl teeth. The switch alsoengages contacts 55 and 55, completing a circuit for the armature 5? ofthe driving motor IE to start movement of the stairway in the updirection, the motor field 59 being illustrated as connected directlyacross the supply wires. The up direction switch also engages contacts58 to prepare a holding circuit. This holding circuit is completed whenthe stairway comes up to substantially full speed, in the circuitsillustrated, by the closing of handrail speed responsive switch 451 forone side of the stairway and the closing of corresponding handrail speedresponsive switch 39 for the other side of the stairway. The starting ofthe moving stairway in the down di rection is effected in a similarmanner. by pressing one of the down starting buttons 48 or 50, downdirection switch D being operated instead of up direction switch U. Tostop the stairway,

The handrail mechanism forone of the stop buttons 5| or 52 is pressed,breaking the circuit for the coil of the operated direction switch,which drops out to deenergize the release magnet of the stairway brakeand disconnect the armature of the driving motor from the supply lines,the brake acting to bring the stairway to a stop if descending and toprevent its reversal after stopping if ascending.

Assume that the stairway is in operation and that, for example, one ormore persons at the side of the stairway take hold of the handrail atthat side and either pull on the handrail if it be moving away from themor push on it if it be moving toward them. By exerting suflicient force,they may cause the handrail to lose its traction so that it slips withrespect to newel wheel 35 and return wheel 36. A similar condition mayarise when the handrail of an ascending stairway is ridden, the forcedue to the weight of the person or persons on the handrail which actsagainst the driving force being augmented by the increased frictionbetween the handrail and the balustrading. This condition may arise fromother causes, such as something becoming jammed between the handrail andthe balustrade in the opening in the balustrade to receive the handrail.These various situations are known tohave arisen.

Slipping of the handrail on its driving sheaves may only slow it down orit may bring it to a stop, depending upon the amount of the forceexerted in opposition to the driving force. In any event, the lowernewel wheel 38, being driven by the handrail, accurately registers itsspeed and this registration is transmitted to speed responsive switch 39or 40. Thus, whenever an appreciable decrease in the speed of eitherhandrail takes place, the speed responsive switch for that handrailopens to break the circuit for the coil of the operated directionswitch, whereupon the stairway is brought to a stop. Thus, thepossibility of accidents due to a change in the speed of either handrailwith respect to the speed of the steps is minimized.

It is to be understood that any form of speed responsive device may beutilized, the arrangement shown being intended to illustratediagrammatically a form of device which may be utilized. Also, thepositioning of the speed responsive devices and the manner in which theyare driven maybe arranged to suit the particular installation, anyarrangement which will register a de-' crease in the speed of eitherhandrail with respect to that of the steps being satisfactory. Variousdetails of the moving stairway may be changed. For example, a form ofbrake may be provided which acts to exert a braking action to stop thestairway. when either descending or ascending. Also, the invention maybe applied to other forms of moving stairway construction, the formshown being chosen for convenience of illustration.

Therefore, as many apparently widely difierent embodiments of thisinvention may be made without departing from the scope thereof, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:

1. A moving stairway comprising, a series of steps, a handrail,mechanism for driving said steps and handrail in synchronism, and meansresponsive to a decrease in speed of the handrail below that of thesteps for bringing said steps and the handrail to a stop.

2. A moving stairway comprising, a series of steps, a handrail,mechanism for driving said steps and handrail in synchronism, and meansresponsive to the speed of the handrail for bringing said steps and thehandrail to a stopwhen the speed of the handrail falls below that of thesteps.

3. A moving stairway comprising, a series of steps, a handrail,mechanism for conjointly driving said steps and handrail, and meansresponsive to the speed of the handrail for bringing said drivingmechanism to a stop upon the slowing down or stopping of the handrail.

4. A moving stairway comprising, a series of steps, a handrail,mechanism for moving said steps and handrail conjointly, an electricmotor for driving said mechanism, a source of current for said motor,switching means for connecting said motor to said source, and meansresponsive to the speed of the handrail for causing operation of saidswitching means, upon the slowing down or stopping of the handrail, todisconnect said motor from said source and bring said mechanism to astop.

5. A moving stairway comprising, a series of steps, a handrail having anewel wheel at the upper and lower ends of the stairway, mechanism formoving said steps and handrail conjointly, an electric motor for drivingsaid mechanism, a source of current for said motor, switching means forconnecting said motor to said source, and speed responsive means drivenby one of said handrail newel wheels for causing operation of saidswitching means, when the speed of the handrail falls below that of thesteps, to disconnect said motor from said source.

6. A moving stairway comprising, a series of steps, a pair of handrails,one on each side of the stairway, each handrail extending around a newelwheel at the upper and lower ends of the stairway, mechanism for movingsaid steps and handrail conjointly, said mechanism in moving saidhandrails operating through the newel wheels at the upper end of thestairway, an electric motor for driving said mechanism, a source ofcurrent for said motor, switching means for connecting said motor tosaid source, and a device for each handrail responsive to the speedthereof, each device being driven by the newel wheel at the lower end ofthe stairway for the handrail for which the device is provided andacting, when the speed of such handrail falls below that of the steps,to cause operation of said switching means to disconnect said motor fromsaid source.

' ARTHUR EDWARD HANDY.

